Over the weekend, Bank of America Merrill Lynch wrote a big note on how we moved from a place of arguing for more austerity from governments — that is: less debt, more taxes — and towards a place where the consensus is that governments need to do more spending.

And when it comes to the US, the case for more spending — aside from sluggish overall economic growth — can be plainly found in the old age of the government's stuff.

Here's BAML (emphasis mine):

"Low infrastructure spending has translated into an increasing average age of government fixed assets from 21.8 years in 2009 to 23.7 in 2014. Structures are the main driver, with the average age rising from 24.7 to 26.7. The American Society of Civil Engineers (ASCE) gave the US's infrastructure a 'GPA' of 'D+' in 2013.

They estimate that the US has an investment need of $3.3tn between 2016 and 2025 and planned investment of just $1.8tn, which leaves a $1.4tn gap. According to the report, the area with the greatest need is surface transportation, with an estimated investment gap of $1.1tn. Even if these numbers overstate the problem, there is plenty of room for improvement."

And the chart from BAML is pretty clear: our stuff is old. Time to fix it.